Novak Djokovic quickly got back in the groove after his Australian Open triumph with a crushing defeat of Olivier Rochus as Serbia surged into a 2-0 lead in their Davis Cup, first round tie in Belgium.
Holders Czech Republic were locked at 1-1 after the first day against a Switzerland side minus world number two Roger Federer - Tomas Berdych levelling the tie after Lukas Rosol had been outplayed by Stanislas Wawrinka.
France and Kazakhstan made impressive starts to their ties against Israel and Austria respectively while top seeds Spain were in action later against Canada in Vancouver.
Germany's hopes of beating Argentina in Buenos Aires suffered a cruel blow, however, as Philipp Kohlschreiber was forced to retire with a hamstring injury when serving for the match at 5-4 in the fifth set against Carlos Berlocq.
Less than a week after claiming a third consecutive Australian Open title by beating Andy Murray in Melbourne, world number one Djokovic quickly adapted to the indoor clay court at the Spiroudome in Charleroi to blow away Rochus 6-3 6-2 6-2.
Serbia's Viktor Troicki, playing in place of the absent Janko Tipsarevic, battled back from two sets down to beat David Goffin in the opening rubber.
Troicki, who won the deciding rubber when Serbia beat France to win the Davis Cup for the first time in 2010, produced a gutsy display after being outplayed for two sets.
Friday's match began to spin away from Goffin in the third set as Troicki clawed his way back to win 1-6 3-6 7-6 6-4 6-4.
On the eve of the match, Serbia had criticised the playing surface, saying the decision to lay a clay court on top of a wooden floor was dangerous.
The International Tennis Federation (ITF) issued a statement saying they were happy with the court and it seemed fine for Djokovic who fired down 20 aces in a one hour 39 minute breeze.
A strong France lineup had too much for visitors Israel on the opening day in Rouen.
Jo-Wilfried Tsonga needed four sets to beat Amir Weintraub before Richard Gasquet made short work of Dudi Sela.
"It is the perfect scenario because we've got two wins under our belt," team captain Arnaud Clement told reporters. "We will need to be very focused so we can wrap this up tomorrow."
In other ties ,Croatia moved ahead against Italy in Turin thanks to Marin Cilic's five-set win against Paolo Lorenzi.
The United States, who have won the competition a record 32 times, face Brazil in Jacksonville later on Friday.